The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of alkylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, now becoming known as polyketones or polyketone polymers, has become of greater interest in part because of the greater availability of the polymers. More recent processes for the production of the polyketone polymers are illustrated by a number of published European Patent Applications including 121,965, 181,014, 213,671 and 257,633. The process, now considered conventional, generally involves the use of a catalyst formed from a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below about 6, preferably below 2, and a bidentate ligand of phosphorous, arsenic or antimony.
The resulting polymers are relatively high molecular weight materials having established utility as premium thermoplastics in the production of shaped articles by methods conventional for the processing of thermoplastics. Although the polymers are relatively stable, the linear alternating polymers do undergo to some degree the degradation caused by exposure to ultraviolet light and elevated temperature characteristic of most if not all organic polymers.
Russell et al, U.S. Pat. No. 3,929,729 and U.S. Pat. No. 4,024,104 teach the use of certain benzophenones and benzotriazines as thermal stabilizers for certain polymers of carbon monoxide and ethylene with the optional presence of third monomers. Although the scope of the disclosed polymers is rather broad the scope of polymers tested is rather narrow and the Russell et al teachings do not appear to be directed toward linear alternating polymers. In copending U.S. patent application Ser. No. 167,801, filed Mar. 14, 1988, there is disclosed a class of stabilizers useful to retard degradation of the linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon. Copending U.S. patent application Ser. No. 343,770, filed Apr. 27, 1989 discloses a synergistic combination of a diphenylamine and a particular type of channel-type carbon black to retard the degradation caused by exposure to ultraviolet light. It would be of advantage, however, to provide an additional stabilizer package useful in preventing degradation of a linear alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon upon exposure to ultraviolet light.